Fix linter errors

src/django_clickhouse/database.py

@@ -1,5 +1,5 @@
 import logging
-from typing import Generator, Optional, Type, Iterable
+from typing import Optional, Type, Iterable
 
 from infi.clickhouse_orm.database import Database as InfiDatabase, DatabaseException
 from infi.clickhouse_orm.utils import parse_tsv
@@ -35,8 +35,8 @@ class Database(InfiDatabase):
     def _get_applied_migrations(self, migrations_package_name):
         raise NotImplementedError("This method is not supported by django_clickhouse.")
 
-    def select_tuples(self, query: str, model_class: Type['ClickHouseModel'], settings: Optional[dict] = None
-                      ) -> Iterable[tuple]:
+    def select_tuples(self, query: str, model_class: Type['ClickHouseModel'],  # noqa: F821
+                      settings: Optional[dict] = None) -> Iterable[tuple]:
         """
         This method selects model_class namedtuples, instead of class instances.
         Less memory consumption, greater speed
@@ -67,7 +67,7 @@ class Database(InfiDatabase):
 
                 yield item
 
-    def insert_tuples(self, model_class: Type['ClickHouseModel'], model_tuples: Iterable[tuple],
+    def insert_tuples(self, model_class: Type['ClickHouseModel'], model_tuples: Iterable[tuple],  # noqa: F821
                       batch_size: Optional[int] = None, formatted: bool = False) -> None:
         """
         Inserts model_class namedtuples

src/django_clickhouse/models.py

@@ -155,7 +155,7 @@ class ClickHouseSyncModel(DjangoModel):
         return storage_cls()
 
     @classmethod
-    def register_clickhouse_sync_model(cls, model_cls: Type['ClickHouseModel']) -> None:
+    def register_clickhouse_sync_model(cls, model_cls: Type['ClickHouseModel']) -> None:  # noqa: F821
         """
         Registers ClickHouse model to listen to this model updates
         :param model_cls: Model class to register
@@ -167,7 +167,7 @@ class ClickHouseSyncModel(DjangoModel):
         cls._clickhouse_sync_models.add(model_cls)
 
     @classmethod
-    def get_clickhouse_sync_models(cls) -> Set['ClickHouseModel']:
+    def get_clickhouse_sync_models(cls) -> Set['ClickHouseModel']:  # noqa: F821
         """
         Returns all clickhouse models, listening to this class
         :return: A set of model classes to sync

src/django_clickhouse/serializers.py

@@ -7,7 +7,7 @@ from .utils import model_to_dict
 
 
 class Django2ClickHouseModelSerializer:
-    def __init__(self, model_cls: Type['ClickHouseModel'], fields: Optional[Iterable[str]] = None,
+    def __init__(self, model_cls: Type['ClickHouseModel'], fields: Optional[Iterable[str]] = None,  # noqa: F821
                  exclude_fields: Optional[Iterable[str]] = None, writable: bool = False,
                  defaults: Optional[dict] = None) -> None:
         """